Police in Beijing have detained a 22-year-old woman teacher over allegations of abuse of children at a kindergarten owned by a US-listed education group.

The principal of the RYB Education New World kindergarten in Chaoyang district has also been sacked amid an investigation into claims that children in the school’s care were abused.

According to Chinese media, parents allege that some of the children were molested, had needle marks on their arms and were given unspecified medication. But police have not publicly clarified what kind of claims they are investigating.

The Chaoyang district government said police reports indicated the case was one of malicious harm to children.

“We have asked the kindergarten’s owner to immediately fire the principal, and we will seriously investigate the school and its staff,” the district government said.

Soon after municipal police announced on Saturday that it had detained a 22-year-old teacher identified only by her surname Liu, RYB Education said it had sacked the woman and removed the kindergarten’s principal.

The company also said it would inspect its kindergartens across the country and offer counselling to the affected children.

Chaoyang police said separately that they also detained a 31-year-old Beijing woman for spreading rumours that a military regiment was involved in molesting the children. On Friday, the People’s Liberation Army dismissed the rumours, saying there was no link between serving military officers or their family members and the kindergarten.

RYB’s share price in the United States has plummeted since the allegations surfaced. On Friday, the first trading day after the Thanksgiving holiday in the US, RYB’s share price shed 38 per cent and closed at US$16.40, below its initial public offering price of US$18.50 on September 27.

US law firm Rosen said it was prepared to launch a class action case to recover losses by investors in the company.

This is not the first time that an RYB kindergarten has had to contend with child abuse allegations. Four teachers from one of its kindergartens in Siping, Jilin province, were sentenced to between 30 and 34 months in jail after needle marks were found on the bodies of several pupils in 2015.

The allegations have revived calls for China to introduce a law specifically to address child abuse.

Under Chinese criminal law, child abuse comes under an umbrella that includes abuse of juveniles, the elderly and the disabled.

But Shanghai-based lawyer Zhen Tao said the law’s provisions were too broad and might not be specific enough to support a charge of abuse against the school.